Barron Alexander J, Lesperance Danielle N A, Doucette Jeremy, Calle Sthefany, Broderick Nichole A
Department of Biology, Johns Hopkins University, Baltimore, MD 21218 U.S.A.
Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269 U.S.A.
bioRxiv. 2023 Jan 12:2023.01.12.523836. doi: 10.1101/2023.01.12.523836.
Microbial invasions underlie host-microbe interactions that result in microbial pathogenesis and probiotic colonization. While these processes are of broad interest, there are still gaps in our understanding of the barriers to entry and how some microbes overcome them. In this study, we explore the effects of the microbiome on invasions of foreign microbes in . We demonstrate that gut microbes and improve survival during invasion of a lethal gut pathogen and lead to a reduction in microbial burden. Using a novel multi-organism interactions assay, we report that inhibits the growth of three invasive Gram-negative bacteria, while prevents this inhibition. A series of and experiments revealed that inhibition by is linked to its ability to acidify both internal and external environments, including culture media, fly food, and the gut itself, while diminishes the inhibition by quenching acids. We propose that acid produced by the microbiome serves as an important gatekeeper to microbial invasions, as only microbes capable of tolerating acidic environments can colonize the host. The methods described herein will add to the growing breadth of tools to study microbe-microbe interactions in broad contexts.
微生物入侵是宿主与微生物相互作用的基础，这种相互作用会导致微生物致病和益生菌定殖。虽然这些过程备受广泛关注，但我们对入侵屏障以及一些微生物如何克服这些屏障的理解仍存在差距。在本研究中，我们探讨了微生物群对体外异物微生物入侵的影响。我们证明肠道微生物和在致死性肠道病原体入侵期间提高了存活率，并导致微生物负荷降低。使用一种新型的多生物体相互作用检测方法，我们报告称抑制三种侵袭性革兰氏阴性菌的生长，而可防止这种抑制作用。一系列和实验表明，的抑制作用与其酸化内部和外部环境（包括培养基、果蝇食物和肠道本身）的能力有关，而通过淬灭酸来减少这种抑制作用。我们提出，微生物群产生的酸是微生物入侵的重要守门人，因为只有能够耐受酸性环境的微生物才能在宿主体内定殖。本文所述方法将为在广泛背景下研究微生物-微生物相互作用增添越来越多的工具。
